Mechanical evaluation for silicon nitride sintered by 28GHz millimeter-wave heating

Abstract

This chapter discusses the mechanical evaluation for silicon nitride sintered by 28GHz millimeter-wave heating. Silicon nitride has many advantages, but it is difficult sintering without additives. Therefore, some oxides are used as the additives. Yb203, can expect the improvement of the mechanical properties but it is difficult to make high density. As a result, it obtained the high-density sintered bodies, with Yb203 and A1203. Sintering temperature is lower than conventional heating, which explores high strength, and is very effective for the energy saving and mechanical properties improvement. It combined nitrogen pressurization and annealing with millimeter-wave heating, to sinter a silicon nitride, which added Yb203 and A1203. The sintering temperature by millimeter wave heating is 1650ºC, which is 200ºC lower compared with the conventional external heating method. The mechanical properties of the sintered body showed a high strength value, under the wide range temperature condition. It can effectively measure the mechanical properties by the non-destruction, which could be confirmed for ceramics materials.